The Panther Address Book now has an icon in the title bar. Option-Click on the icon, pause, then drag and a vCard of the current contact will be created where you release the mouse. If you do the same thing without Option then an Alias to that contact's vCard is created. Either the vCard or the alias can be dragged to supported applications and will open the vCard for viewing the contents. If you drag it back to Address Book it will be considered a duplicate and the duplicate options sheet opens.

If you don't pause before dragging, the entire window is dragged with the mouse.

Also, as I discovered by necessity, you can drag the vCard icon to your signature and it will be attached to every email (if you use a the signature regularly).

Actually I have not verified but it showed up when I applied the signature I created. I looked for options today and only found the script for Entourage; I could not apply a script to an outgoing Mail.app message so I thought I was hosed.